Methods for depositing coatings on aerospace components

ABSTRACT

Protective coatings on an aerospace component are provided. An aerospace component includes a surface containing nickel, nickel superalloy, aluminum, chromium, iron, titanium, hafnium, alloys thereof, or any combination thereof, and a coating disposed on the surface, where the coating contains a nanolaminate film stack having two or more pairs of a first deposited layer and a second deposited layer. The first deposited layer contains chromium oxide, chromium nitride, aluminum oxide, aluminum nitride, or any combination thereof, the second deposited layer contains aluminum oxide, aluminum nitride, silicon oxide, silicon nitride, silicon carbide, yttrium oxide, yttrium nitride, yttrium silicon nitride, hafnium oxide, hafnium nitride, hafnium silicide, hafnium silicate, titanium oxide, titanium nitride, titanium silicide, titanium silicate, or any combination thereof, and the first deposited layer and the second deposited layer have different compositions from each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. application Ser.No. 16/356,688, filed Mar. 18, 2019, which claims benefit to U.S. Appl.No. 62/767,420, filed on Nov. 14, 2018, U.S. Appl. No. 62/644,608, filedon Mar. 19, 2018, and U.S. Appl. No. 62/644,645, filed on Mar. 19, 2018,which are herein incorporated by reference.

BACKGROUND Field

Embodiments of the present disclosure generally relate to depositionprocesses, and in particular to vapor deposition processes fordepositing films on aerospace components.

Description of the Related Art

Turbine engines typically have components which corrode or degrade overtime due to being exposed to hot gases and/or reactive chemicals (e.g.,acids, bases, or salts). Such turbine components are often protected bya thermal and/or chemical barrier coating. The current coatings used onairfoils exposed to the hot gases of combustion in gas turbine enginesfor both environmental protection and as bond coats in thermal barriercoating (TBC) systems include both diffusion aluminides and variousmetal alloy coatings. These coatings are applied over substratematerials, typically nickel-based superalloys, to provide protectionagainst oxidation and corrosion attack. These coatings are formed on thesubstrate in a number of different ways. For example, a nickel aluminidelayer may be grown as an outer coat on a nickel base superalloy bysimply exposing the substrate to an aluminum rich environment atelevated temperatures. The aluminum diffuses into the substrate andcombines with the nickel to form an outer surface of the nickel-aluminumalloy.

A platinum modified nickel aluminide coating can be formed by firstelectroplating platinum to a predetermined thickness over thenickel-based substrate. Exposure of the platinum-plated substrate to analuminum-rich environment at elevated temperatures causes the growth ofan outer region of the nickel-aluminum alloy containing platinum insolid solution. In the presence of excess aluminum, theplatinum-aluminum has two phases that may precipitate in the NiAl matrixas the aluminum diffuses into and reacts with the nickel and platinum.

However, as the increased demands for engine performance elevate theengine operating temperatures and/or the engine life requirements,improvements in the performance of coatings when used as environmentalcoatings or as bond coatings are needed over and above the capabilitiesof these existing coatings. Because of these demands, a coating that canbe used for environmental protection or as a bond coat capable ofwithstanding higher operating temperatures or operating for a longerperiod of time before requiring removal for repair, or both, is desired.These known coating materials and deposition techniques have severalshortcomings. Most metal alloy coatings deposited by low pressure plasmaspray, plasma vapor deposition (PVD), electron beam PVD (EBPVD),cathodic arc, or similar sputtering techniques are line of sightcoatings, meaning that interiors of components are not able to becoated. Platinum electroplating of exteriors typically forms areasonably uniform coating, however, electroplating the interior of acomponent has proven to be challenging. The resulting electroplatingcoatings are often too thin to be protective or too thick that there areother adverse mechanical effects, such as high weight gain or fatiguelife debit. Similarly, aluminide coatings suffer from non-uniformity oninterior passages of components. Aluminide coatings are brittle, whichcan lead to reduced life when exposed to fatigue.

In addition, most of these coatings are on the order of greater than 10micrometers in thickness, which can cause component weight to increase,making design of the disks and other support structures morechallenging. Many of these coatings also require high temperature (e.g.,greater than 500° C.) steps to deposit or promote enough interdiffusionof the coating into the alloy to achieve adhesion. It is desired by manyto have coatings that (1) protect metals from oxidation and corrosion,(2) are capable of high film thickness and composition uniformity onarbitrary geometries, (3) have high adhesion to the metal, (4) aresufficiently thin to not materially increase weight or reduce fatiguelife outside of current design practices for bare metal, and/or (5) aredeposited at sufficiently low temperature (e.g., 500° C. or less) to notcause microstructural changes to the metal.

Therefore, improved protective coatings and methods for depositing theprotective coatings are needed.

SUMMARY

Embodiments of the present disclosure generally relate to protectivecoatings on aerospace components and methods for depositing theprotective coatings. In one or more embodiments, an aerospace componentincludes a surface comprising nickel, nickel superalloy, aluminum,chromium, iron, titanium, hafnium, alloys thereof, or any combinationthereof, and a coating disposed on the surface, where the coatingcontains a nanolaminate film stack having two or more pairs of a firstdeposited layer and a second deposited layer. The first deposited layercontains chromium oxide, chromium nitride, aluminum oxide, aluminumnitride, or any combination thereof, and the second deposited layercontains aluminum oxide, aluminum nitride, silicon oxide, siliconnitride, silicon carbide, yttrium oxide, yttrium nitride, yttriumsilicon nitride, hafnium oxide, hafnium nitride, hafnium silicide,hafnium silicate, titanium oxide, titanium nitride, titanium silicide,titanium silicate, or any combination thereof. The first deposited layerand the second deposited layer have different compositions from eachother. The nanolaminate film stack has a thickness of about 1 nm toabout 5,000 nm.

In some embodiments, an aerospace component includes a surfacecomprising nickel or nickel superalloy, and a coating disposed on thesurface, where the coating contains a coalesced film formed by annealinga nanolaminate film stack which has two or more alternating layers of afirst deposited layer and a second deposited layer. The first depositedlayer contains chromium oxide, chromium nitride, aluminum oxide,aluminum nitride, or any combination thereof, the second deposited layercontains aluminum oxide, aluminum nitride, silicon oxide, siliconnitride, silicon carbide, yttrium oxide, yttrium nitride, yttriumsilicon nitride, hafnium oxide, hafnium nitride, hafnium silicide,hafnium silicate, titanium oxide, titanium nitride, titanium silicide,titanium silicate, or any combination thereof, the first deposited layerand the second deposited layer have different compositions from eachother.

In other embodiments, a turbine blade includes a surface containingnickel or nickel superalloy, and a coating disposed on the surface,where the coating contain a coalesced film formed by annealing ananolaminate film stack which contains two or more alternating layers ofa first deposited layer and a second deposited layer. The firstdeposited layer contains chromium oxide, chromium nitride, aluminumoxide, aluminum nitride, or any combination thereof, the seconddeposited layer contains aluminum oxide, aluminum nitride, siliconoxide, silicon nitride, silicon carbide, yttrium oxide, yttrium nitride,yttrium silicon nitride, hafnium oxide, hafnium nitride, hafniumsilicide, hafnium silicate, titanium oxide, titanium nitride, titaniumsilicide, titanium silicate, or any combination thereof, and the firstdeposited layer and the second deposited layer have differentcompositions from each other.

In one or more embodiments, a method for depositing a coating on anaerospace component includes exposing an aerospace component to a firstprecursor and a first reactant to form a first deposited layer on asurface of the aerospace component by a chemical vapor deposition (CVD)process or a first atomic layer deposition (ALD) process and exposingthe aerospace component to a second precursor and a second reactant toform a second deposited layer on the first deposited layer by a secondALD process, where the first deposited layer and the second depositedlayer have different compositions from each other.

In some embodiments, a method for depositing a coating on an aerospacecomponent includes forming a nanolaminate film stack on a surface of theaerospace component, where the nanolaminate film stack containsalternating layers of a first deposited layer and a second depositedlayer. The method includes sequentially exposing the aerospace componentto a first precursor and a first reactant to form the first depositedlayer on the surface by ALD, where the first deposited layer containschromium oxide, chromium nitride, aluminum oxide, aluminum nitride, orany combination thereof. The method also includes sequentially exposingthe aerospace component to a second precursor and a second reactant toform the second deposited layer on the first deposited layer by ALD,where the second deposited layer contains aluminum oxide, aluminumnitride, silicon oxide, silicon nitride, silicon carbide, yttrium oxide,yttrium nitride, yttrium silicon nitride, hafnium oxide, hafniumnitride, hafnium silicide, hafnium silicate, titanium oxide, titaniumnitride, titanium silicide, titanium silicate, or any combinationthereof, and where the first deposited layer and the second depositedlayer have different compositions from each other.

In other embodiments, an aerospace component contains a surfacecomprising nickel, nickel superalloy, aluminum, chromium, iron,titanium, hafnium, alloys thereof, or any combination thereof and acoating disposed on the surface, where the coating contains ananolaminate film stack which includes alternating layers of a firstdeposited layer and a second deposited layer. The first deposited layercontains chromium oxide, chromium nitride, aluminum oxide, aluminumnitride, or any combination thereof. The second deposited layer containsaluminum oxide, aluminum nitride, silicon oxide, silicon nitride,silicon carbide, yttrium oxide, yttrium nitride, yttrium siliconnitride, hafnium oxide, hafnium nitride, hafnium silicide, hafniumsilicate, titanium oxide, titanium nitride, titanium silicide, titaniumsilicate, or any combination thereof. The first deposited layer and thesecond deposited layer have different compositions from each other andthe nanolaminate film stack has a thickness of about 1 nm to about 5,000nm, such as about 10 nm to about 800 nm.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlyexemplary embodiments and are therefore not to be considered limiting ofits scope, may admit to other equally effective embodiments.

FIG. 1 is a flow chart of a method for depositing a coating on anaerospace component, according to one or more embodiments described anddiscussed herein.

FIGS. 2A and 2B are schematic views of protective coatings disposed on asurface of an aerospace component, according to one or more embodimentsdescribed and discussed herein.

FIGS. 3A and 3B are schematic views of an aerospace component containingone or more protective coatings, according to one or more embodimentsdescribed and discussed herein.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe Figures. It is contemplated that elements and features of one ormore embodiments may be beneficially incorporated in other embodiments.

DETAILED DESCRIPTION

Embodiments of the present disclosure generally relate to protectivecoatings, such as nanolaminate film stacks or coalesced films, disposedon an aerospace components and methods for depositing the protectivecoatings. Aerospace components as described and discussed herein can beor include one or more turbine blades, turbine vanes, ribs, fins, pinfins, combustor fuel nozzles, combustor shields, or any other aerospacecomponent or part that can benefit from having protective coatingdeposited thereon. The protective coatings can be deposited or otherwiseformed on interior surfaces and/or exterior surfaces of the aerospacecomponents.

In one or more embodiments, a method for depositing a protective coatingon an aerospace component includes sequentially exposing the aerospacecomponent to a chromium precursor and a reactant to form achromium-containing layer on a surface the aerospace component by anatomic layer deposition (ALD) process. The chromium-containing layercontains metallic chromium, chromium oxide, chromium nitride, chromiumcarbide, chromium silicide, or any combination thereof.

In some embodiments, a nanolaminate film stack is formed on the surfaceof the aerospace component, where the nanolaminate film stack containsalternating layers of the chromium-containing layer and a seconddeposited layer. The aerospace component can be sequentially exposed toa metal or silicon precursor and a second reactant to form the seconddeposited layer on the surface by ALD. The second deposited layercontains aluminum oxide, aluminum nitride, silicon oxide, siliconnitride, silicon carbide, yttrium oxide, yttrium nitride, yttriumsilicon nitride, hafnium oxide, hafnium nitride, hafnium silicide,hafnium silicate, titanium oxide, titanium nitride, titanium silicide,titanium silicate, or any combination thereof. The nanolaminate filmstack containing the alternating layers of the chromium-containing layerand the second deposited layer can be used as the protective coating onthe aerospace component. Alternatively, in other embodiments, thenanolaminate film stack disposed on the aerospace component can beexposed to an annealing process to convert the nanolaminate film stackinto a coalesced film, which can be used as the protective coating onthe aerospace component.

FIG. 1 is a flow chart of a method 100 for depositing a coating on oneor more aerospace components, according to one or more embodimentsdescribed and discussed herein. FIGS. 2A and 2B are schematic views ofprotective coatings 200 and 250 disposed on a surface of the aerospacecomponent 202, according to one or more embodiments described anddiscussed herein. The protective coatings 200 and 250 can be depositedor otherwise formed on the aerospace component 202 by the method 100described and discussed below.

In one or more embodiments, the protective coating 200 contains ananolaminate film stack 230 containing one pair or a plurality of pairsof a first deposited layer 210 and a second deposited layer 220sequentially deposited or otherwise formed on the aerospace component202, as depicted in FIG. 2A. The nanolaminate film stack 230 isillustrated with four pairs of the first and second deposited layers210, 220, however, the nanolaminate film stack 230 can contain anynumber of the first and second deposited layers 210, 220, as furtherdiscussed below. For example, the nanolaminate film stack 230 cancontain from one pair of the first and second deposited layers 210, 220to about 150 pairs of the first and second deposited layers 210, 220. Inother embodiments, not shown, the protective coating 200 is not ananolaminate film stack, but instead contains the first deposited layer210 or the second deposited layer 220 deposited or otherwise formed onthe aerospace component 202. In further embodiments, the nanolaminatefilm stack 230 containing one or more pairs of the first and seconddeposited layers 210, 220 is initially deposited, then is converted to acoalesced film 240, such as illustrated by the protective coating 250depicted in FIG. 2B.

At block 110, prior to producing the protective coating 200 or 250, theaerospace component 202 can optionally be exposed to one or morepre-clean processes. The surfaces of the aerospace component 202 cancontain oxides, organics, oil, soil, particulate, debris, and/or othercontaminants are removed prior to producing the protective coating 200or 250 on the aerospace component 202. The pre-clean process can be orinclude one or more basting or texturing processes, vacuum purges,solvent clean, acid clean, wet clean, plasma clean, sonication, or anycombination thereof. Once cleaned and/or textured, the subsequentlydeposited protective coating 200 or 250 has stronger adhesion to thesurfaces of the aerospace component 202 than if otherwise not exposed tothe pre-clean process.

In one or more examples, the surfaces of the aerospace component 202 canbe blasted with or otherwise exposed to beads, sand, carbonate, or otherparticulates to remove oxides and other contaminates therefrom and/or toprovide texturing to the surfaces of the aerospace component 202. Insome examples, the aerospace component 202 can be placed into a chamberwithin a pulsed push-pull system and exposed to cycles of purge gas(e.g., N₂, Ar, He, or any combination thereof) and vacuum purges toremove debris from small holes on the aerospace component 202. In otherexamples, the surfaces of the aerospace component 202 can be exposed tohydrogen plasma, oxygen or ozone plasma, and/or nitrogen plasma, whichcan be generated in a plasma chamber or by a remote plasma system.

In one or more examples, such as for organic removal or oxide removal,the surfaces of the aerospace component 202 can be exposed to a hydrogenplasma, then degassed, then exposed to ozone treatment. In otherexamples, such as for organic removal, the surfaces of the aerospacecomponent 202 can be exposed to a wet clean that includes: soaking in analkaline degreasing solution, rinsing, exposing the surfaces to an acidclean (e.g., sulfuric acid, phosphoric acid, or hydrochloric acid),rinsing, and exposing the surfaces deionized water sonication bath. Insome examples, such as for oxide removal, the surfaces of the aerospacecomponent 202 can be exposed to a wet clean that includes: exposing thesurfaces to a dilute acid solution (e.g., acetic acid or hydrochloricacid), rinsing, and exposing the surfaces deionized water sonicationbath. In one or more examples, such as for particle removal, thesurfaces of the aerospace component 202 can be exposed to sonication(e.g., megasonication) and/or a supercritical carbon dioxide wash,followed by exposing to cycles of purge gas (e.g., N₂, Ar, He, or anycombination thereof) and vacuum purges to remove particles from and drythe surfaces. In some examples, the aerospace component 202 can beexposed to heating or drying processes, such as heating the aerospacecomponent 202 to a temperature of about 50° C., about 65° C., or about80° C. to about 100° C., about 120° C., or about 150° C. and exposing tosurfaces to the purge gas. The aerospace component 202 can be heated inan oven or exposed to lamps for the heating or drying processes.

At block 120, the aerospace component 202 can be exposed to a firstprecursor and a first reactant to form the first deposited layer 210 onthe aerospace component 202 by a vapor deposition process, as depictedin FIG. 2A. The vapor deposition process can be an ALD process, aplasma-enhanced ALD (PE-ALD) process, a thermal chemical vapordeposition (CVD) process, a plasma-enhanced CVD (PE-CVD) process, or anycombination thereof.

In one or more embodiments, the vapor deposition process is an ALDprocess and the method includes sequentially exposing the surface of theaerospace component 202 to the first precursor and the first reactant toform the first deposited layer 210. Each cycle of the ALD processincludes exposing the surface of the aerospace component to the firstprecursor, conducting a pump-purge, exposing the aerospace component tothe first reactant, and conducting a pump-purge to form the firstdeposited layer 210. The order of the first precursor and the firstreactant can be reversed, such that the ALD cycle includes exposing thesurface of the aerospace component to the first reactant, conducting apump-purge, exposing the aerospace component to the first precursor, andconducting a pump-purge to form the first deposited layer 210.

In some examples, during each ALD cycle, the aerospace component 202 isexposed to the first precursor for about 0.1 seconds to about 10seconds, the first reactant for about 0.1 seconds to about 10 seconds,and the pump-purge for about 0.5 seconds to about 30 seconds. In otherexamples, during each ALD cycle, the aerospace component 202 is exposedto the first precursor for about 0.5 seconds to about 3 seconds, thefirst reactant for about 0.5 seconds to about 3 seconds, and thepump-purge for about 1 second to about 10 seconds.

Each ALD cycle is repeated from 2, 3, 4, 5, 6, 8, about 10, about 12, orabout 15 times to about 18, about 20, about 25, about 30, about 40,about 50, about 65, about 80, about 100, about 120, about 150, about200, about 250, about 300, about 350, about 400, about 500, about 800,about 1,000, or more times to form the first deposited layer. Forexample, each ALD cycle is repeated from 2 times to about 1,000 times, 2times to about 800 times, 2 times to about 500 times, 2 times to about300 times, 2 times to about 250 times, 2 times to about 200 times, 2times to about 150 times, 2 times to about 120 times, 2 times to about100 times, 2 times to about 80 times, 2 times to about 50 times, 2 timesto about 30 times, 2 times to about 20 times, 2 times to about 15 times,2 times to about 10 times, 2 times to 5 times, about 8 times to about1,000 times, about 8 times to about 800 times, about 8 times to about500 times, about 8 times to about 300 times, about 8 times to about 250times, about 8 times to about 200 times, about 8 times to about 150times, about 8 times to about 120 times, about 8 times to about 100times, about 8 times to about 80 times, about 8 times to about 50 times,about 8 times to about 30 times, about 8 times to about 20 times, about8 times to about 15 times, about 8 times to about 10 times, about 20times to about 1,000 times, about 20 times to about 800 times, about 20times to about 500 times, about 20 times to about 300 times, about 20times to about 250 times, about 20 times to about 200 times, about 20times to about 150 times, about 20 times to about 120 times, about 20times to about 100 times, about 20 times to about 80 times, about 20times to about 50 times, about 20 times to about 30 times, about 50times to about 1,000 times, about 50 times to about 500 times, about 50times to about 350 times, about 50 times to about 300 times, about 50times to about 250 times, about 50 times to about 150 times, or about 50times to about 100 times to form the first deposited layer 210.

In other embodiments, the vapor deposition process is a CVD process andthe method includes simultaneously exposing the aerospace component 202to the first precursor and the first reactant to form the firstdeposited layer 210. During an ALD process or a CVD process, each of thefirst precursor and the first reactant can independent include one ormore carrier gases. One or more purge gases can be flowed across theaerospace component and/or throughout the processing chamber in betweenthe exposures of the first precursor and the first reactant. In someexamples, the same gas may be used as a carrier gas and a purge gas.Exemplary carrier gases and purge gases can independently be or includeone or more of nitrogen (N₂), argon, helium, neon, hydrogen (H₂), or anycombination thereof.

The first deposited layer 210 can have a thickness of about 0.1 nm,about 0.2 nm, about 0.3 nm, about 0.4 nm, about 0.5 nm, about 0.8 nm,about 1 nm, about 2 nm, about 3 nm, about 5 nm, about 8 nm, about 10 nm,about 12 nm, or about 15 nm to about 18 nm, about 20 nm, about 25 nm,about 30 nm, about 40 nm, about 50 nm, about 60 nm, about 80 nm, about100 nm, about 120 nm, or about 150 nm. For example, the first depositedlayer 210 can have a thickness of about 0.1 nm to about 150 nm, about0.2 nm to about 150 nm, about 0.2 nm to about 120 nm, about 0.2 nm toabout 100 nm, about 0.2 nm to about 80 nm, about 0.2 nm to about 50 nm,about 0.2 nm to about 40 nm, about 0.2 nm to about 30 nm, about 0.2 nmto about 20 nm, about 0.2 nm to about 10 nm, about 0.2 nm to about 5 nm,about 0.2 nm to about 1 nm, about 0.2 nm to about 0.5 nm, about 0.5 nmto about 150 nm, about 0.5 nm to about 120 nm, about 0.5 nm to about 100nm, about 0.5 nm to about 80 nm, about 0.5 nm to about 50 nm, about 0.5nm to about 40 nm, about 0.5 nm to about 30 nm, about 0.5 nm to about 20nm, about 0.5 nm to about 10 nm, about 0.5 nm to about 5 nm, about 0.5nm to about 1 nm, about 2 nm to about 150 nm, about 2 nm to about 120nm, about 2 nm to about 100 nm, about 2 nm to about 80 nm, about 2 nm toabout 50 nm, about 2 nm to about 40 nm, about 2 nm to about 30 nm, about2 nm to about 20 nm, about 2 nm to about 10 nm, about 2 nm to about 5nm, about 2 nm to about 3 nm, about 10 nm to about 150 nm, about 10 nmto about 120 nm, about 10 nm to about 100 nm, about 10 nm to about 80nm, about 10 nm to about 50 nm, about 10 nm to about 40 nm, about 10 nmto about 30 nm, about 10 nm to about 20 nm, or about 10 nm to about 15nm.

In one or more embodiments, the first precursor contains one or morechromium precursors, one or more aluminum precursors, or one or morehafnium precursors. The first reactant contains one or more reducingagents, one or more oxidizing agents, one or more nitriding agents, oneor more silicon precursors, one or more carbon precursors, or anycombination thereof. In some examples, the first deposited layer 210 isa chromium-containing layer which can be or include metallic chromium,chromium oxide, chromium nitride, chromium silicide, chromium carbide,or any combination thereof. In other examples, the first deposited layer210 is an aluminum-containing layer which can be or include metallicaluminum, aluminum oxide, aluminum nitride, aluminum silicide, aluminumcarbide, or any combination thereof. In further examples, the firstdeposited layer 210 is a hafnium-containing layer which can be orinclude metallic hafnium, hafnium oxide, hafnium nitride, hafniumsilicide, hafnium carbide, or any combination thereof.

The chromium precursor can be or include one or more of chromiumcyclopentadiene compounds, chromium carbonyl compounds, chromiumacetylacetonate compounds, chromium diazadienyl compounds, substitutesthereof, complexes thereof, abducts thereof, salts thereof, or anycombination thereof. Exemplary chromium precursor can be or includebis(cyclopentadiene) chromium (Cp₂Cr), bis(pentamethylcyclopentadiene)chromium ((Me₅Cp)₂Cr), bis(isoproplycyclopentadiene) chromium((iPrCp)₂Cr), bis(ethylbenzene) chromium ((EtBz)₂Cr), chromiumhexacarbonyl (Cr(CO)₆), chromium acetylacetonate (Cr(acac)₃, also knownas, tris(2,4-pentanediono) chromium), chromium hexafluoroacetylacetonate(Cr(hfac)₃), chromium(III) tris(2,2,6,6-tetramethyl-3,5-heptanedionate){Cr(tmhd)₃}, chromium(II) bis(1,4-ditertbutyldiazadienyl), isomersthereof, complexes thereof, abducts thereof, salts thereof, or anycombination thereof. Exemplary chromium diazadienyl compounds can have achemical formula of:

where each R and R′ is independently selected from H, C1-C6 alkyl, aryl,acyl, alkylamido, hydrazido, silyl, aldehyde, keto, C2-C4 alkenyl,alkynyl, or substitutes thereof. In some examples, each R isindependently a C1-C6 alkyl which is selected from methyl, ethyl,propyl, butyl, or isomers thereof, and R′ is H. For example, R is methyland R′ is H, R is ethyl and R′ is H, R is iso-propyl and R′ is H, or Ris tert-butyl and R′ is H.

The aluminum precursor can be or include one or more of aluminum alkylcompounds, one or more of aluminum alkoxy compounds, one or more ofaluminum acetylacetonate compounds, substitutes thereof, complexesthereof, abducts thereof, salts thereof, or any combination thereof.Exemplary aluminum precursors can be or include trimethylaluminum,triethylaluminum, tripropylaluminum, tributylaluminum,trimethoxyaluminum, triethoxyaluminum, tripropoxyaluminum,tributoxyaluminum, aluminum acetylacetonate (Al(acac)₃, also known as,tris(2,4-pentanediono) aluminum), aluminum hexafluoroacetylacetonate(Al(hfac)₃), trisdipivaloylmethanatoaluminum (DPM₃Al; (C₁₁H₁₉O₂)₃Al),isomers thereof, complexes thereof, abducts thereof, salts thereof, orany combination thereof.

The hafnium precursor can be or include one or more of hafniumcyclopentadiene compounds, one or more of hafnium amino compounds, oneor more of hafnium alkyl compounds, one or more of hafnium alkoxycompounds, substitutes thereof, complexes thereof, abducts thereof,salts thereof, or any combination thereof. Exemplary hafnium precursorscan be or include bis(methylcyclopentadiene) dimethylhafnium((MeCp)₂HfMe₂), bis(methylcyclopentadiene) methylmethoxyhafnium((MeCp)₂Hf(OMe)(Me)), bis(cyclopentadiene) dimethylhafnium ((Cp)₂HfMe₂),tetra(tert-butoxy) hafnium, hafniumum isopropoxide ((iPrO)₄Hf),tetrakis(dimethylamino) hafnium (TDMAH), tetrakis(diethylamino) hafnium(TDEAH), tetrakis(ethylmethylamino) hafnium (TEMAH), isomers thereof,complexes thereof, abducts thereof, salts thereof, or any combinationthereof.

The titanium precursor can be or include one or more of titaniumcyclopentadiene compounds, one or more of titanium amino compounds, oneor more of titanium alkyl compounds, one or more of titanium alkoxycompounds, substitutes thereof, complexes thereof, abducts thereof,salts thereof, or any combination thereof. Exemplary titanium precursorscan be or include bis(methylcyclopentadiene) dimethyltitanium((MeCp)₂TiMe₂), bis(methylcyclopentadiene) methylmethoxytitanium((MeCp)₂Ti(OMe)(Me)), bis(cyclopentadiene) dimethyltitanium((Cp)₂TiMe₂), tetra(tert-butoxy) titanium, titaniumum isopropoxide((iPrO)₄Ti), tetrakis(dimethylamino) titanium (TDMAT),tetrakis(diethylamino) titanium (TDEAT), tetrakis(ethylmethylamino)titanium (TEMAT), isomers thereof, complexes thereof, abducts thereof,salts thereof, or any combination thereof.

In one or more examples, the first deposited layer 210 is achromium-containing layer which can be or include metallic chromium andthe first reactant contains one or more reducing agents. In someexamples, the first deposited layer 210 is an aluminum-containing layerwhich can be or include metallic aluminum and the first reactantcontains one or more reducing agents. In other examples, the firstdeposited layer 210 is a hafnium-containing layer which can be orinclude metallic hafnium and the first reactant contains one or morereducing agents. Exemplary reducing agents can be or include hydrogen(H₂), ammonia, hydrazine, one or more hydrazine compounds, one or morealcohols, a cyclohexadiene, a dihydropyrazine, an aluminum containingcompound, abducts thereof, salts thereof, plasma derivatives thereof, orany combination thereof.

In some examples, the first deposited layer 210 is a chromium-containinglayer which can be or include chromium oxide and the first reactantcontains one or more oxidizing agents. In other examples, the firstdeposited layer 210 is an aluminum-containing layer which can be orinclude aluminum oxide and the first reactant contains one or moreoxidizing agents. In further examples, the first deposited layer 210 isa hafnium-containing layer which can be or include hafnium oxide and thefirst reactant contains one or more oxidizing agents. Exemplaryoxidizing agents can be or include water (e.g., steam), oxygen (O₂),atomic oxygen, ozone, nitrous oxide, one or more peroxides, one or morealcohols, plasmas thereof, or any combination thereof.

In one or more examples, the first deposited layer 210 is achromium-containing layer which can be or include chromium nitride andthe first reactant contains one or more nitriding agents. In otherexamples, the first deposited layer 210 is an aluminum-containing layerwhich can be or include aluminum nitride and the first reactant containsone or more nitriding agents. In some examples, the first depositedlayer 210 is a hafnium-containing layer which can be or include hafniumnitride and the first reactant contains one or more nitriding agents.Exemplary nitriding agents can be or include ammonia, atomic nitrogen,one or more hydrazines, nitric oxide, plasmas thereof, or anycombination thereof.

In one or more examples, the first deposited layer 210 is achromium-containing layer which can be or include chromium silicide andthe first reactant contains one or more silicon precursors. In someexamples, the first deposited layer 210 is an aluminum-containing layerwhich can be or include aluminum silicide and the first reactantcontains one or more silicon precursors. In other examples, the firstdeposited layer 210 is a hafnium-containing layer which can be orinclude hafnium silicide and the first reactant contains one or moresilicon precursors. Exemplary silicon precursors can be or includesilane, disilane, trisilane, tetrasilane, pentasilane, hexasilane,monochlorosilane, dichlorosilane, trichlorosilane, tetrachlorosilane,hexachlorosilane, substituted silanes, plasma derivatives thereof, orany combination thereof.

In some examples, the first deposited layer 210 is a chromium-containinglayer which can be or include chromium carbide and the first reactantcontains one or more carbon precursors. In other examples, the firstdeposited layer 210 is an aluminum-containing layer which can be orinclude aluminum carbide and the first reactant contains one or morecarbon precursors. In further examples, the first deposited layer 210 isa hafnium-containing layer which can be or include hafnium carbide andthe first reactant contains one or more carbon precursors. Exemplarycarbon precursors can be or include one or more alkanes, one or morealkenes, one or more alkynes, substitutes thereof, plasmas thereof, orany combination thereof.

At block 130, the aerospace component 202 is exposed to a secondprecursor and a second reactant to form the second deposited layer 220on the first deposited layer 210 by an ALD process producingnanolaminate film. The first deposited layer 210 and second depositedlayer 220 have different compositions from each other. In some examples,the first precursor is a different precursor than the second precursor,such as that the first precursor is a source of a first type of metaland the second precursor is a source of a second type of metal and thefirst and second types of metal are different.

The second precursor can be or include one or more aluminum precursorsone or more hafnium precursors, one or more yttrium precursors, or anycombination thereof. The second reactant can be any other reactants usedas the first reactant. For example, the second reactant can be orinclude one or more reducing agents, one or more oxidizing agents, oneor more nitriding agents, one or more silicon precursors, one or morecarbon precursors, or any combination thereof, as described anddiscussed above. During the ALD process, each of the second precursorand the second reactant can independent include one or more carriergases. One or more purge gases can be flowed across the aerospacecomponent and/or throughout the processing chamber in between theexposures of the second precursor and the second reactant. In someexamples, the same gas may be used as a carrier gas and a purge gas.Exemplary carrier gases and purge gases can independently be or includeone or more of nitrogen (N₂), argon, helium, neon, hydrogen (H₂), or anycombination thereof.

In one or more embodiments, the second deposited layer 220 containsaluminum oxide, aluminum nitride, silicon oxide, silicon nitride,silicon carbide, yttrium oxide, yttrium nitride, yttrium siliconnitride, hafnium oxide, hafnium nitride, hafnium silicide, hafniumsilicate, titanium oxide, titanium nitride, titanium silicide, titaniumsilicate, or any combination thereof. In one or more examples, if thefirst deposited layer 210 contains aluminum oxide or aluminum nitride,then the second deposited layer 220 does not contain aluminum oxide oraluminum nitride. Similarly, if the first deposited layer 210 containshafnium oxide or hafnium nitride, then the second deposited layer 220does not contain hafnium oxide or hafnium nitride.

Each cycle of the ALD process includes exposing the aerospace componentto the second precursor, conducting a pump-purge, exposing the aerospacecomponent to the second reactant, and conducting a pump-purge to formthe second deposited layer 220. The order of the second precursor andthe second reactant can be reversed, such that the ALD cycle includesexposing the surface of the aerospace component to the second reactant,conducting a pump-purge, exposing the aerospace component to the secondprecursor, and conducting a pump-purge to form the second depositedlayer 220.

In one or more examples, during each ALD cycle, the aerospace component202 is exposed to the second precursor for about 0.1 seconds to about 10seconds, the second reactant for about 0.1 seconds to about 10 seconds,and the pump-purge for about 0.5 seconds to about 30 seconds. In otherexamples, during each ALD cycle, the aerospace component 202 is exposedto the second precursor for about 0.5 seconds to about 3 seconds, thesecond reactant for about 0.5 seconds to about 3 seconds, and thepump-purge for about 1 second to about 10 seconds.

Each ALD cycle is repeated from 2, 3, 4, 5, 6, 8, about 10, about 12, orabout 15 times to about 18, about 20, about 25, about 30, about 40,about 50, about 65, about 80, about 100, about 120, about 150, about200, about 250, about 300, about 350, about 400, about 500, about 800,about 1,000, or more times to form the second deposited layer 220. Forexample, each ALD cycle is repeated from 2 times to about 1,000 times, 2times to about 800 times, 2 times to about 500 times, 2 times to about300 times, 2 times to about 250 times, 2 times to about 200 times, 2times to about 150 times, 2 times to about 120 times, 2 times to about100 times, 2 times to about 80 times, 2 times to about 50 times, 2 timesto about 30 times, 2 times to about 20 times, 2 times to about 15 times,2 times to about 10 times, 2 times to 5 times, about 8 times to about1,000 times, about 8 times to about 800 times, about 8 times to about500 times, about 8 times to about 300 times, about 8 times to about 250times, about 8 times to about 200 times, about 8 times to about 150times, about 8 times to about 120 times, about 8 times to about 100times, about 8 times to about 80 times, about 8 times to about 50 times,about 8 times to about 30 times, about 8 times to about 20 times, about8 times to about 15 times, about 8 times to about 10 times, about 20times to about 1,000 times, about 20 times to about 800 times, about 20times to about 500 times, about 20 times to about 300 times, about 20times to about 250 times, about 20 times to about 200 times, about 20times to about 150 times, about 20 times to about 120 times, about 20times to about 100 times, about 20 times to about 80 times, about 20times to about 50 times, about 20 times to about 30 times, about 50times to about 1,000 times, about 50 times to about 500 times, about 50times to about 350 times, about 50 times to about 300 times, about 50times to about 250 times, about 50 times to about 150 times, or about 50times to about 100 times to form the second deposited layer 220.

The second deposited layer 220 can have a thickness of about 0.1 nm,about 0.2 nm, about 0.3 nm, about 0.4 nm, about 0.5 nm, about 0.8 nm,about 1 nm, about 2 nm, about 3 nm, about 5 nm, about 8 nm, about 10 nm,about 12 nm, or about 15 nm to about 18 nm, about 20 nm, about 25 nm,about 30 nm, about 40 nm, about 50 nm, about 60 nm, about 80 nm, about100 nm, about 120 nm, or about 150 nm. For example, the second depositedlayer 220 can have a thickness of about 0.1 nm to about 150 nm, about0.2 nm to about 150 nm, about 0.2 nm to about 120 nm, about 0.2 nm toabout 100 nm, about 0.2 nm to about 80 nm, about 0.2 nm to about 50 nm,about 0.2 nm to about 40 nm, about 0.2 nm to about 30 nm, about 0.2 nmto about 20 nm, about 0.2 nm to about 10 nm, about 0.2 nm to about 5 nm,about 0.2 nm to about 1 nm, about 0.2 nm to about 0.5 nm, about 0.5 nmto about 150 nm, about 0.5 nm to about 120 nm, about 0.5 nm to about 100nm, about 0.5 nm to about 80 nm, about 0.5 nm to about 50 nm, about 0.5nm to about 40 nm, about 0.5 nm to about 30 nm, about 0.5 nm to about 20nm, about 0.5 nm to about 10 nm, about 0.5 nm to about 5 nm, about 0.5nm to about 1 nm, about 2 nm to about 150 nm, about 2 nm to about 120nm, about 2 nm to about 100 nm, about 2 nm to about 80 nm, about 2 nm toabout 50 nm, about 2 nm to about 40 nm, about 2 nm to about 30 nm, about2 nm to about 20 nm, about 2 nm to about 10 nm, about 2 nm to about 5nm, about 2 nm to about 3 nm, about 10 nm to about 150 nm, about 10 nmto about 120 nm, about 10 nm to about 100 nm, about 10 nm to about 80nm, about 10 nm to about 50 nm, about 10 nm to about 40 nm, about 10 nmto about 30 nm, about 10 nm to about 20 nm, or about 10 nm to about 15nm.

In some examples, the first deposited layer 210 is a chromium-containinglayer that contains chromium oxide, chromium nitride, or a combinationthereof, and the second deposited layer 220 contains one or more ofaluminum oxide, silicon nitride, hafnium oxide, hafnium silicate,titanium oxide, or any combination thereof.

At block 140, the method 100 includes deciding whether or not a desiredthickness of the nanolaminate film stack 230 has been achieved. If thedesired thickness of the nanolaminate film stack 230 has been achieved,then move to block 150. If the desired thickness of the nanolaminatefilm stack 230 has not been achieved, then start another depositioncycle of depositing the first deposited layer 210 by the vapordeposition process at block 120 and depositing the second depositedlayer 220 by the ALD process at block 130. The deposition cycle isrepeated until achieving the desired thickness of the nanolaminate filmstack 230.

In one or more embodiments, the protective coating 200 or thenanolaminate film stack 230 can contain from 1, 2, 3, 4, 5, 6, 7, 8, or9 pairs of the first and second deposited layers 210, 220 to about 10,about 12, about 15, about 20, about 25, about 30, about 40, about 50,about 65, about 80, about 100, about 120, about 150, about 200, about250, about 300, about 500, about 800, or about 1,000 pairs of the firstand second deposited layers 210, 220. For example, the nanolaminate filmstack 230 can contain from 1 to about 1,000, 1 to about 800, 1 to about500, 1 to about 300, 1 to about 250, 1 to about 200, 1 to about 150, 1to about 120, 1 to about 100, 1 to about 80, 1 to about 65, 1 to about50, 1 to about 30, 1 to about 20, 1 to about 15, 1 to about 10, 1 toabout 8, 1 to about 6, 1 to 5, 1 to 4, 1 to 3, about 5 to about 150,about 5 to about 120, about 5 to about 100, about 5 to about 80, about 5to about 65, about 5 to about 50, about 5 to about 30, about 5 to about20, about 5 to about 15, about 5 to about 10, about 5 to about 8, about5 to about 7, about 10 to about 150, about 10 to about 120, about 10 toabout 100, about 10 to about 80, about 10 to about 65, about 10 to about50, about 10 to about 30, about 10 to about 20, about 10 to about 15, orabout 10 to about 12 pairs of the first and second deposited layers 210,220.

The protective coating 200 or the nanolaminate film stack 230 can have athickness of about 1 nm, about 2 nm, about 3 nm, about 5 nm, about 8 nm,about 10 nm, about 12 nm, about 15 nm, about 20 nm, about 30 nm, about50 nm, about 60 nm, about 80 nm, about 100 nm, or about 120 nm to about150 nm, about 180 nm, about 200 nm, about 250 nm, about 300 nm, about350 nm, about 400 nm, about 500 nm, about 800 nm, about 1,000 nm, about2,000 nm, about 3,000 nm, about 4,000 nm, about 5,000 nm, about 6,000nm, about 7,000 nm, about 8,000 nm, about 9,000 nm, about 10,000 nm, orthicker. In some examples, the protective coating 200 or thenanolaminate film stack 230 can have a thickness of less than 10 μm(less than 10,000 nm). For example, the protective coating 200 or thenanolaminate film stack 230 can have a thickness of about 1 nm to lessthan 10,000 nm, about 1 nm to about 8,000 nm, about 1 nm to about 6,000nm, about 1 nm to about 5,000 nm, about 1 nm to about 3,000 nm, about 1nm to about 2,000 nm, about 1 nm to about 1,500 nm, about 1 nm to about1,000 nm, about 1 nm to about 500 nm, about 1 nm to about 400 nm, about1 nm to about 300 nm, about 1 nm to about 250 nm, about 1 nm to about200 nm, about 1 nm to about 150 nm, about 1 nm to about 100 nm, about 1nm to about 80 nm, about 1 nm to about 50 nm, about 20 nm to about 500nm, about 20 nm to about 400 nm, about 20 nm to about 300 nm, about 20nm to about 250 nm, about 20 nm to about 200 nm, about 20 nm to about150 nm, about 20 nm to about 100 nm, about 20 nm to about 80 nm, about20 nm to about 50 nm, about 30 nm to about 400 nm, about 30 nm to about200 nm, about 50 nm to about 500 nm, about 50 nm to about 400 nm, about50 nm to about 300 nm, about 50 nm to about 250 nm, about 50 nm to about200 nm, about 50 nm to about 150 nm, about 50 nm to about 100 nm, about80 nm to about 250 nm, about 80 nm to about 200 nm, about 80 nm to about150 nm, about 80 nm to about 100 nm, about 50 nm to about 80 nm, about100 nm to about 500 nm, about 100 nm to about 400 nm, about 100 nm toabout 300 nm, about 100 nm to about 250 nm, about 100 nm to about 200nm, or about 100 nm to about 150 nm.

At block 150, the nanolaminate film stack 230 can optionally be exposedto one or more annealing processes. In some examples, the nanolaminatefilm stack 230 can be converted into the coalesced film 240 during theannealing process. During the annealing process, the high temperaturecoalesces the layers within the nanolaminate film stack 230 into asingle structure where the new crystalline assembly enhances theintegrity and protective properties of the coalesced film 240. In otherexamples, the nanolaminate film stack 230 can be heated and densifiedduring the annealing process, but still maintained as a nanolaminatefilm stack. The annealing process can be or include a thermal anneal, aplasma anneal, an ultraviolet anneal, a laser anneal, or any combinationthereof.

The nanolaminate film stack 230 disposed on the aerospace component 202is heated to a temperature of about 400° C., about 500° C., about 600°C., or about 700° C. to about 750° C., about 800° C., about 900° C.,about 1,000° C., about 1,100° C., about 1,200° C., or greater during theannealing process. For example, the nanolaminate film stack 230 disposedon the aerospace component 202 is heated to a temperature of about 400°C. to about 1,200° C., about 400° C. to about 1,100° C., about 400° C.to about 1,000° C., about 400° C. to about 900° C., about 400° C. toabout 800° C., about 400° C. to about 700° C., about 400° C. to about600° C., about 400° C. to about 500° C., about 550° C. to about 1,200°C., about 550° C. to about 1,100° C., about 550° C. to about 1,000° C.,about 550° C. to about 900° C., about 550° C. to about 800° C., about550° C. to about 700° C., about 550° C. to about 600° C., about 700° C.to about 1,200° C., about 700° C. to about 1,100° C., about 700° C. toabout 1,000° C., about 700° C. to about 900° C., about 700° C. to about800° C., about 850° C. to about 1,200° C., about 850° C. to about 1,100°C., about 850° C. to about 1,000° C., or about 850° C. to about 900° C.during the annealing process.

The nanolaminate film stack 230 can be under a vacuum at a low pressure(e.g., from about 0.1 Torr to less than 760 Torr), at ambient pressure(e.g., about 760 Torr), and/or at a high pressure (e.g., from greaterthan 760 Torr (1 atm) to about 3,678 Torr (about 5 atm)) during theannealing process. The nanolaminate film stack 230 can be exposed to anatmosphere containing one or more gases during the annealing process.Exemplary gases used during the annealing process can be or includenitrogen (N₂), argon, helium, hydrogen (H₂), oxygen (O₂), or anycombinations thereof. The annealing process can be performed for about0.01 seconds to about 10 minutes. In some examples, the annealingprocess can be a thermal anneal and lasts for about 1 minute, about 5minutes, about 10 minutes, or about 30 minutes to about 1 hour, about 2hours, about 5 hours, or about 24 hours. In other examples, theannealing process can be a laser anneal or a spike anneal and lasts forabout 1 millisecond, about 100 millisecond, or about 1 second to about 5seconds, about 10 seconds, or about 15 seconds.

The protective coating 250 or the coalesced film 240 can have athickness of about 1 nm, about 2 nm, about 3 nm, about 5 nm, about 8 nm,about 10 nm, about 12 nm, about 15 nm, about 20 nm, about 30 nm, about50 nm, about 60 nm, about 80 nm, about 100 nm, or about 120 nm to about150 nm, about 180 nm, about 200 nm, about 250 nm, about 300 nm, about350 nm, about 400 nm, about 500 nm, about 700 nm, about 850 nm, about1,000 nm, about 1,200 nm, about 1,500 nm, about 2,000 nm, about 3,000nm, about 4,000 nm, about 5,000 nm, about 6,000 nm, about 7,000 nm,about 8,000 nm, about 9,000 nm, about 10,000 nm, or thicker. In someexamples, the protective coating 250 or the coalesced film 240 can havea thickness of less than 10 μm (less than 10,000 nm). For example, theprotective coating 250 or the coalesced film 240 can have a thickness ofabout 1 nm to less than 10,000 nm, about 1 nm to about 8,000 nm, about 1nm to about 6,000 nm, about 1 nm to about 5,000 nm, about 1 nm to about3,000 nm, about 1 nm to about 2,000 nm, about 1 nm to about 1,500 nm,about 1 nm to about 1,000 nm, about 1 nm to about 500 nm, about 1 nm toabout 400 nm, about 1 nm to about 300 nm, about 1 nm to about 250 nm,about 1 nm to about 200 nm, about 1 nm to about 150 nm, about 1 nm toabout 100 nm, about 1 nm to about 80 nm, about 1 nm to about 50 nm,about 20 nm to about 500 nm, about 20 nm to about 400 nm, about 20 nm toabout 300 nm, about 20 nm to about 250 nm, about 20 nm to about 200 nm,about 20 nm to about 150 nm, about 20 nm to about 100 nm, about 20 nm toabout 80 nm, about 20 nm to about 50 nm, about 30 nm to about 400 nm,about 30 nm to about 200 nm, about 50 nm to about 500 nm, about 50 nm toabout 400 nm, about 50 nm to about 300 nm, about 50 nm to about 250 nm,about 50 nm to about 200 nm, about 50 nm to about 150 nm, about 50 nm toabout 100 nm, about 80 nm to about 250 nm, about 80 nm to about 200 nm,about 80 nm to about 150 nm, about 80 nm to about 100 nm, about 50 nm toabout 80 nm, about 100 nm to about 500 nm, about 100 nm to about 400 nm,about 100 nm to about 300 nm, about 100 nm to about 250 nm, about 100 nmto about 200 nm, or about 100 nm to about 150 nm.

In one or more embodiments, the protective coatings 200 and 250 can havea relatively high degree of uniformity. The protective coatings 200 and250 can have a uniformity of less than 50%, less than 40%, or less than30% of the thickness of the respective protective coating 200, 250. Theprotective coatings 200 and 250 can independently have a uniformity fromabout 0%, about 0.5%, about 1%, about 2%, about 3%, about 5%, about 8%,or about 10% to about 12%, about 15%, about 18%, about 20%, about 22%,about 25%, about 28%, about 30%, about 35%, about 40%, about 45%, orless than 50% of the thickness. For example, the protective coatings 200and 250 can independently have a uniformity from about 0% to about 50%,about 0% to about 40%, about 0% to about 30%, about 0% to less than 30%,about 0% to about 28%, about 0% to about 25%, about 0% to about 20%,about 0% to about 15%, about 0% to about 10%, about 0% to about 8%,about 0% to about 5%, about 0% to about 3%, about 0% to about 2%, about0% to about 1%, about 1% to about 50%, about 1% to about 40%, about 1%to about 30%, about 1% to less than 30%, about 1% to about 28%, about 1%to about 25%, about 1% to about 20%, about 1% to about 15%, about 1% toabout 10%, about 1% to about 8%, about 1 to about 5%, about 1% to about3%, about 1% to about 2%, about 5% to about 50%, about 5% to about 40%,about 5% to about 30%, about 5% to less than 30%, about 5% to about 28%,about 5% to about 25%, about 5% to about 20%, about 5% to about 15%,about 5% to about 10%, about 5% to about 8%, about 10% to about 50%,about 10% to about 40%, about 10% to about 30%, about 10% to less than30%, about 10% to about 28%, about 10% to about 25%, about 10% to about20%, about 10% to about 15%, or about 10% to about 12% of the thickness.

In some embodiments, the protective coatings 200 and/or 250 contain canbe formed or otherwise produced with different ratios of metalsthroughout the material, such as a doping metal or grading metalcontained within a base metal, where any of the metal can be in anychemically oxidized form (e.g., oxide, nitride, silicide, carbide, orcombinations thereof). In one or more examples, the first depositedlayer 210 is deposited to first thickness and the second deposited layer220 is deposited to a second thickness, where the first thickness orless than or greater than the second thickness. For example, the firstdeposited layer 210 can be deposited by two or more (3, 4, 5, 6, 7, 8,9, 10, or more) ALD cycles during block 120 to produce the respectivelysame amount of sub-layers (e.g., one sub-layer for each ALD cycle), andthen the second deposited layer 220 can be deposited by one ALD cycle ora number of ALD cycles that is less than or greater than the number ofALD cycles used to deposit the first deposited layer 210. In otherexamples, the first deposited layer 210 can be deposited by CVD to afirst thickness and the second deposited layer 220 is deposited by ALDto a second thickness which is less than the first thickness.

In other embodiments, an ALD process can be used to deposit the firstdeposited layer 210 and/or the second deposited layer 220 where thedeposited material is doped by including a dopant precursor during theALD process. In some examples, the dopant precursor can be included aseparate ALD cycle relative to the ALD cycles used to deposit the basematerial. In other examples, the dopant precursor can be co-injectedwith any of the chemical precursors used during the ALD cycle. Infurther examples, the dopant precursor can be injected separate from thechemical precursors during the ALD cycle. For example, one ALD cycle caninclude exposing the aerospace component to: the first precursor, apump-purge, the dopant precursor, a pump-purge, the first reactant, anda pump-purge to form the deposited layer. In some examples, one ALDcycle can include exposing the aerospace component to: the dopantprecursor, a pump-purge, the first precursor, a pump-purge, the firstreactant, and a pump-purge to form the deposited layer. In otherexamples, one ALD cycle can include exposing the aerospace component to:the first precursor, the dopant precursor, a pump-purge, the firstreactant, and a pump-purge to form the deposited layer.

In one or more embodiments, the first deposited layer 210 and/or thesecond deposited layer 220 contains one or more base materials and oneor more doping materials. The base material is or contains aluminumoxide, chromium oxide, or a combination of aluminum oxide and chromiumoxide. The doping material is or contains hafnium, hafnium oxide,yttrium, yttrium oxide, cerium, cerium oxide, silicon, silicon oxide,nitrides thereof, or any combination thereof. Any of the precursors orreagents described herein can be used as a doping precursor or a dopant.Exemplary cerium precursor can be or include one or more cerium(IV)tetra(2,2,6,6-tetramethyl-3,5-heptanedionate) (Ce(TMHD)₄),tris(cyclopentadiene) cerium ((C₅H₅)₃Ce), tris(propylcyclopentadiene)cerium ([(C₃H₇)C₅H₄]₃Ce), tris(tetramethylcyclopentadiene) cerium([(CH₃)₄C₅H]₃Ce), or any combination thereof.

The doping material can have a concentration of about 0.01 atomicpercent (at %), about 0.05 at %, about 0.08 at %, about 0.1 at %, about0.5 at %, about 0.8 at %, about 1 at %, about 1.2 at %, about 1.5 at %,about 1.8 at %, or about 2 at % to about 2.5 at %, about 3 at %, about3.5 at %, about 4 at %, about 5 at %, about 8 at %, about 10 at %, about15 at %, about 20 at %, about 25 at %, or about 30 at % within the firstdeposited layer 210, the second deposited layer 220, the nanolaminatefilm stack 230, and/or the coalesced film 240. For example, the dopingmaterial can have a concentration of about 0.01 at % to about 30 at %,about 0.01 at % to about 25 at %, about 0.01 at % to about 20 at %,about 0.01 at % to about 15 at %, about 0.01 at % to about 12 at %,about 0.01 at % to about 10 at %, about 0.01 at % to about 8 at %, about0.01 at % to about 5 at %, about 0.01 at % to about 4 at %, about 0.01at % to about 3 at %, about 0.01 at % to about 2.5 at %, about 0.01 at %to about 2 at %, about 0.01 at % to about 1.5 at %, about 0.01 at % toabout 1 at %, about 0.01 at % to about 0.5 at %, about 0.01 at % toabout 0.1 at %, about 0.1 at % to about 30 at %, about 0.1 at % to about25 at %, about 0.1 at % to about 20 at %, about 0.1 at % to about 15 at%, about 0.1 at % to about 12 at %, about 0.1 at % to about 10 at %,about 0.1 at % to about 8 at %, about 0.1 at % to about 5 at %, about0.1 at % to about 4 at %, about 0.1 at % to about 3 at %, about 0.1 at %to about 2.5 at %, about 0.1 at % to about 2 at %, about 0.1 at % toabout 1.5 at %, about 0.1 at % to about 1 at %, about 0.1 at % to about0.5 at %, about 1 at % to about 30 at %, about 1 at % to about 25 at %,about 1 at % to about 20 at %, about 1 at % to about 15 at %, about 1 at% to about 12 at %, about 1 at % to about 10 at %, about 1 at % to about8 at %, about 1 at % to about 5 at %, about 1 at % to about 4 at %,about 1 at % to about 3 at %, about 1 at % to about 2.5 at %, about 1 at% to about 2 at %, or about 1 at % to about 1.5 at % within the firstdeposited layer 210, the second deposited layer 220, the nanolaminatefilm stack 230, and/or the coalesced film 240.

In one or more embodiments, the protective coating 200 includes thenanolaminate film stack 230 having the first deposited layer 210containing aluminum oxide (or other base material) and the seconddeposited layer 220 containing hafnium oxide (or other doping material),or having the first deposited layer 210 containing hafnium oxide (orother doping material) and the second deposited layer 220 containingaluminum oxide (or other base material). In one or more examples, theprotective coatings 200 and/or 250 contain a combination of aluminumoxide and hafnium oxide, a hafnium-doped aluminum oxide, hafniumaluminate, or any combination thereof. For example, the protectivecoating 200 includes the nanolaminate film stack 230 having the firstdeposited layer 210 contains aluminum oxide and the second depositedlayer 220 contains hafnium oxide, or having the first deposited layer210 contains hafnium oxide and the second deposited layer 220 containsaluminum oxide. In other examples, the protective coating 250 includesthe coalesced film 240 formed from layers of aluminum oxide and hafniumoxide. In one or more embodiments, the protective coating 200 or 250 hasa concentration of hafnium (or other doping material) of about 0.01 at%, about 0.05 at %, about 0.08 at %, about 0.1 at %, about 0.5 at %,about 0.8 at %, or about 1 at % to about 1.2 at %, about 1.5 at %, about1.8 at %, about 2 at %, about 2.5 at %, about 3 at %, about 3.5 at %,about 4 at %, about 4.5 at %, or about 5 at % within the nanolaminatefilm stack 230 or the coalesced film 240 containing aluminum oxide (orother base material). For example, the protective coating 200 or 250 hasa concentration of hafnium (or other doping material) of about 0.01 at %to about 10 at %, about 0.01 at % to about 8 at %, about 0.01 at % toabout 5 at %, about 0.01 at % to about 4 at %, about 0.01 at % to about3 at %, about 0.01 at % to about 2.5 at %, about 0.01 at % to about 2 at%, about 0.01 at % to about 1.5 at %, about 0.01 at % to about 1 at %,about 0.01 at % to about 0.5 at %, about 0.01 at % to about 0.1 at %,about 0.01 at % to about 0.05 at %, about 0.1 at % to about 5 at %,about 0.1 at % to about 4 at %, about 0.1 at % to about 3 at %, about0.1 at % to about 2.5 at %, about 0.1 at % to about 2 at %, about 0.1 at% to about 1.5 at %, about 0.1 at % to about 1 at %, about 0.1 at % toabout 0.5 at %, about 0.5 at % to about 5 at %, about 0.5 at % to about4 at %, about 0.5 at % to about 3 at %, about 0.5 at % to about 2.5 at%, about 0.5 at % to about 2 at %, about 0.5 at % to about 1.5 at %,about 0.5 at % to about 1 at %, about 1 at % to about 5 at %, about 1 at% to about 4 at %, about 1 at % to about 3 at %, about 1 at % to about2.5 at %, about 1 at % to about 2 at %, or about 1 at % to about 1.5 at% within the nanolaminate film stack 230 or the coalesced film 240containing aluminum oxide (or other base material).

FIGS. 3A and 3B are schematic views of an aerospace component 300containing a protective coating 330, according to one or moreembodiments described and discussed herein. FIG. 3A is a perspectiveview of the aerospace component 300 and FIG. 3B is a cross-sectionalview of the aerospace component 300. The protective coating 330 can beor include one or more nanolaminate film stacks, one or more coalescedfilms, or any combination thereof, as described and discussed herein.For example, the protective coating 330 can be or include the protectivecoating 200 containing the nanolaminate film stack 230 (FIG. 2A) and/orcan be or include the protective coating 250 containing the coalescedfilm 240 (FIG. 2B). Similarly, the aerospace component 300 can be orinclude the aerospace component 202 (FIGS. 2A-2B). Aerospace componentsas described and discussed herein, including aerospace component 300,can be or include one or more components or portions thereof of aturbine, an aircraft, a spacecraft, or other devices that can includeone or more turbines (e.g., compressors, pumps, turbo fans, superchargers, and the like). Exemplary aerospace components 300 can be orinclude a turbine blade, a turbine vane, a support member, a frame, arib, a fin, a pin fin, a combustor fuel nozzle, a combustor shield, aninternal cooling channel, or any combination thereof.

The aerospace component 300 has one or more outer or exterior surfaces310 and one or more inner or interior surfaces 320. The interiorsurfaces 320 can define one or more cavities 302 extending or containedwithin the aerospace component 300. The cavities 302 can be channels,passages, spaces, or the like disposed between the interior surfaces320. The cavity 302 can have one or more openings 304, 306, and 308.Each of the cavities 302 within the aerospace component 300 typicallyhave aspect ratios (e.g., length divided by width) of greater than 1.The methods described and discussed herein provide depositing and/orotherwise forming the protective coatings 200 and 250 on the interiorsurfaces 320 with high aspect ratios (greater than 1) and/or within thecavities 302.

The aspect ratio of the cavity 302 can be from about 2, about 3, about5, about 8, about 10, or about 12 to about 15, about 20, about 25, about30, about 40, about 50, about 65, about 80, about 100, about 120, about150, about 200, about 250, about 300, about 500, about 800, about 1,000,or greater. For example, the aspect ratio of the cavity 302 can be fromabout 2 to about 1,000, about 2 to about 500, about 2 to about 200,about 2 to about 150, about 2 to about 120, about 2 to about 100, about2 to about 80, about 2 to about 50, about 2 to about 40, about 2 toabout 30, about 2 to about 20, about 2 to about 10, about 2 to about 8,about 5 to about 1,000, about 5 to about 500, about 5 to about 200,about 5 to about 150, about 5 to about 120, about 5 to about 100, about5 to about 80, about 5 to about 50, about 5 to about 40, about 5 toabout 30, about 5 to about 20, about 5 to about 10, about 5 to about 8,about 10 to about 1,000, about 10 to about 500, about 10 to about 200,about 10 to about 150, about 10 to about 120, about 10 to about 100,about 10 to about 80, about 10 to about 50, about 10 to about 40, about10 to about 30, about 10 to about 20, about 20 to about 1,000, about 20to about 500, about 20 to about 200, about 20 to about 150, about 20 toabout 120, about 20 to about 100, about 20 to about 80, about 20 toabout 50, about 20 to about 40, or about 20 to about 30.

The aerospace component 300 and any surface thereof including one ormore outer or exterior surfaces 310 and/or one or more inner or interiorsurfaces 320 can be made of, contain, or otherwise include one or moremetals, such as nickel, aluminum, chromium, iron, titanium, hafnium, oneor more nickel superalloys, one or more Inconel alloys, one or moreHastelloy alloys, alloys thereof, or any combination thereof. Theprotective coating 330 can be deposited, formed, or otherwise producedon any surface of the aerospace component 300 including one or moreouter or exterior surfaces 310 and/or one or more inner or interiorsurfaces 320.

The protective coating, as described and discussed herein, can be orinclude one or more of laminate film stacks, coalesced films, gradedcompositions, and/or monolithic films which are deposited or otherwiseformed on any surface of an aerospace component. In some examples, theprotective coating contains from about 1% to about 100% chromium oxide.The protective coatings are conformal and substantially coat roughsurface features following surface topology, including in open pores,blind holes, and non-line-of sight regions of a surface. The protectivecoatings do not substantially increase surface roughness, and in someembodiments, the protective coatings may reduce surface roughness byconformally coating roughness until it coalesces. The protectivecoatings may contain particles from the deposition that aresubstantially larger than the roughness of the aerospace component, butare considered separate from the monolithic film. The protectivecoatings are substantially well adhered and pinhole free. The thicknessof the protective coatings varies within 1-sigma of 40%. In one or moreembodiments, the thickness varies less than 1-sigma of 20%, 10%, 5%, 1%,or 0.1%.

The protective coatings provide corrosion and oxidation protection whenthe aerospace components are exposed to air, oxygen, sulfur and/orsulfur compounds, acids, bases, salts (e.g., Na, K, Mg, Li, or Casalts), or any combination thereof.

One or more embodiments described herein include methods for thepreservation of an underneath chromium-containing alloy using themethods producing an alternating nanolaminate of first material (e.g.,chromium oxide, aluminum oxide, and/or aluminum nitride) and anothersecondary material. The secondary material can be or include one or moreof aluminum oxide, aluminum nitride, aluminum oxynitride, silicon oxide,silicon nitride, silicon carbide, yttrium oxide, yttrium nitride,yttrium silicon nitride, hafnium oxide, hafnium silicate, hafniumsilicide, hafnium nitride, titanium oxide, titanium nitride, titaniumsilicide, titanium silicate, dopants thereof, alloys thereof, or anycombination thereof. The resultant film can be used as a nanolaminatefilm stack or the film can be subjected to annealing where the hightemperature coalesces the films into a single structure where the newcrystalline assembly enhances the integrity and protective properties ofthis overlying film.

In a particular embodiment, the chromium precursor (at a temperature ofabout 0° C. to about 250° C.) is delivered to the aerospace componentvia vapor phase delivery for at pre-determined pulse length of 5seconds. During this process, the deposition reactor is operated under aflow of nitrogen carrier gas (about 1,000 sccm total) with the chamberheld at a pre-determined temperature of about 350° C. and pressure ofabout 3.5 Torr. After the pulse of the chromium precursor, the chamberis then subsequently pumped and purged of all requisite gases andbyproducts for a determined amount of time. Subsequently, water ispulsed into the chamber for 0.1 seconds at chamber pressure of about 3.5Torr. An additional chamber purge (or pump/purge) is then performed torid the reactor of any excess reactants and reaction byproducts. Thisprocess is repeated as many times as necessary to get the target CrOxfilm to the desired film thickness.

For the secondary film (example: aluminum oxide), the precursor,trimethylaluminum (at a temperature of about 0° C. to about 30° C.) isdelivered to the aerospace component via vapor phase delivery for atpre-determined pulse length of 0.1 seconds. During this process, thedeposition reactor is operated under a flow of nitrogen carrier gas (100sccm total) with the chamber held at a pre-determined temperature ofabout 150° C. to about 350° C. and pressure about 1 Torr to about 5Torr. After the pulse of trimethylaluminum, the chamber is thensubsequently pumped and purged of all requisite gases and byproducts fora determined amount of time. Subsequently, water vapor is pulsed intothe chamber for about 0.1 seconds at chamber pressure of about 3.5 Torr.An additional chamber purge is then performed to rid the reactor of anyexcess reactants and reaction byproducts. This process is repeated asmany times as necessary to get the target Al₂O₃ film to the desired filmthickness. The aerospace component is then subjected to an annealingfurnace at a temperature of about 500° C. under inert nitrogen flow ofabout 500 sccm for about one hour.

Doped/Alloyed ALD Layers Processes

One or more embodiments described herein include methods for thepreservation of an underlying aerospace component by using a dopedchromium-containing film. This film is or includes a chromium-containingfilm produced by using a chromium precursor, and one or more of oxygensources or oxidizing agents (for chromium oxide deposition), nitrogensources or nitriding agents (for chromium nitride deposition), one ormore carbon sources or carbon precursors (for chromium carbidedeposition), silicon sources or silicon precursors (for chromiumsilicide deposition), or any combination thereof. A doping precursor (ordopant) can be or include a source for aluminum, yttrium, hafnium,silicon, tantalum, zirconium, strontium, lanthanum, neodymium, holmium,barium, lutetium, dysprosium, samarium, terbium, erbium, thulium,titanium, niobium, manganese, scandium, europium, tin, cerium, or anycombination thereof. The precursors used can be or include, but is notlimited to, one or more chromium precursors, as described and discussedabove. The chromium precursor can be used during a deposition process toproduce doped film containing the ternary material (e.g., YCrO orCrAlO). The resultant film can be used as a nanolaminate film stack orthe film can be subjected to annealing where the high temperaturecoalesces the films into a single structure where the new crystallineassembly enhances the integrity and protective properties of thisoverlying film.

In a particular embodiment, the chromium precursor,bis(1,4-ditertbutyldiazadienyl chromium (II) (at a temperature of about0° C. to about 250° C.) is delivered to the aerospace component viavapor phase delivery for at pre-determined pulse length of 5 seconds.During this process, the deposition reactor is operated under a flow ofnitrogen carrier gas of about 1,000 sccm with the chamber held at apre-determined temperature of about 350° C. and pressure of about 3.5Torr. After the pulse of the chromium precursor, the chamber is thensubsequently pumped and purged of all requisite gases and byproducts fora determined amount of time. Subsequently, a second reactant, water ispulsed into the chamber for 0.1 seconds at chamber pressure of about 3.5Torr. A second chamber purge is then performed to rid the reactor of anyexcess reactants and reaction byproducts.

This chromium precursor/pump-purge/water/pump-purge sequence is repeatedas many times as necessary to get the target CrOx film to the desiredfilm thickness. This process results in the formation of a first CrOxlaminate layer with desired thickness.

After the first CrOx laminate layer deposition, a third reactant,tetrakis(ethylmethylamino)hafnium (TEMAH) is pulsed into the chamber for5 seconds at chamber pressure of about 1.6 Torr. A final chamberpump/purge is then performed to rid the reactor of any excess reactantsand reaction byproducts. Subsequently, a second reactant, water ispulsed into the chamber for 3 seconds at chamber pressure of about 1.2Torr. A second chamber pump/purge is then performed to rid the reactorof any excess reactants and reaction byproducts. This single sequenceresults in the formation of a second HfOx laminate layer with monolayer(HfOx) thickness.

This first CrOx/second HfOx laminate layer sequence is repeated as manytimes as necessary to get the target Hf-doped chromium oxide film(CrOx:Hf) to the desired film thickness. The resultant CrOx:Hf film canbe used as a nanolaminate film stack or the film can be subjected toannealing where the high temperature activates Hf diffusion into a CrOxlayers where the more uniform Hf distribution in CrOx:Hf film enhancesthe integrity and protective properties of this overlying film.

In a particular embodiment, the selected Al precursor, trimethylaluminum(TMAI) (at a temperature of about 0° C. to about 30° C.) is delivered tothe aerospace component via vapor phase delivery for at pre-determinedpulse length of about 0.1 seconds to about 1 second. During thisprocess, the deposition reactor is operated under a flow of nitrogencarrier gas of about 100 sccm with the chamber held at a pre-determinedtemperature of about 150° C. to about 350° C. and pressure of about 1Torr to about 5 Torr. After the pulse of trimethylaluminum, the chamberis then subsequently pumped and purged of all requisite gases andbyproducts for a determined amount of time. Subsequently, water vapor ispulsed into the chamber for 3 seconds at chamber pressure of about 1Torr to about 5 Torr. An additional chamber purge is then performed torid the reactor of any excess reactants and reaction byproducts. Thealuminum precursor/pump-purge/water/pump-purge sequence is repeated asmany times as necessary to get the target AlOx (e.g., Al₂O₃) film to thedesired film thickness. This process results in the formation of a firstAlOx laminate layer with desired thickness.

After first AlOx laminate layer deposition, a third reactant,tetrakis(ethylmethylamino)hafnium (TEMAH) is pulsed into the chamber forabout 5 seconds at chamber pressure of about 1.6 Torr. A final chamberpump/purge is then performed to rid the reactor of any excess reactantsand reaction byproducts. Subsequently, a second reactant, water ispulsed into the chamber for about 3 seconds at chamber pressure of about1.2 Torr. A second chamber pump/purge is then performed to rid thereactor of any excess reactants and reaction byproducts. This singlesequence results in the formation of a second HfOx laminate layer withmonolayer (HfOx) thickness.

This first AlOx/second HfOx laminate layer sequence is repeated as manytimes as necessary to get the target Hf-doped aluminum oxide film(AlOx:Hf) to the desired film thickness. In some examples, the resultantAlOx:Hf film is used as a nanolaminate film stack. In other examples,the resultant AlOx:Hf film is subjected to annealing where the hightemperature activates Hf diffusion into a AlOx layers where the moreuniform Hf distribution in AlOx:Hf film enhances the integrity andprotective properties of this overlying film.

SEM shows cross-sections of ALD as-grown Hf doped Al₂O₃ layers on Siaerospace component. SEM shows cross-section of Hf doped Al₂O₃ layerwith about 0.1 at % Hf concentration. The total Al₂O₃:Hf film thicknessis about 140 nm. The film contains six Al₂O₃/HfO₂ laminate layers. Thesingle Al₂O₃/HfO₂ laminate layer thickness is about 23 nm. SEM showscross-section of Hf doped Al₂O₃ layer with about 0.5 at % Hfconcentration. The total Al₂O₃:Hf film thickness is about 108 nm. Thefilm contains twenty one Al₂O₃/HfO₂ laminate layers. The singleAl₂O₃/HfO₂ laminate layer thickness is about 5.1 nm.

The visual differentiation of HfO₂ and Al₂O₃ layers on SEM cross sectionis clear seen for about 0.1 at % Hf doped sample. However SEM resolution(10 nm) limits the visual differentiation of HfO₂ and Al₂O₃ layers forabout 0.5 at % Hf doped sample. SIMS is used to determine concentrationdepth profiles of ALD as-grown Hf doped Al₂O₃ layers on the aerospacecomponent. A SIMS concentration depth profile of Hf doped Al₂O₃ layer isabout 0.1 at % Hf concentration. The film contains six Al₂O₃/HfO₂laminate layers. A SIMS concentration depth profile of Hf doped Al₂O₃layer is about 0.5 at % Hf concentration. The film contains of twentyone Al₂O₃/HfO₂ laminate layers.

Rutherford backscattering spectrometry (RBS) provides compositionalanalysis data for ALD as-grown Hf doped Al₂O₃ layers. The RBS analysisproved what bulk Al₂O₃:Hf layer with six Al₂O₃/HfO₂ laminate layers hasabout 0.1 at % Hf concentration, and bulk Al₂O₃:Hf layer with twenty oneAl₂O₃/HfO₂ laminate layers has about 0.5 at % Hf concentration.

In one or more embodiments, the protective coatings which includechromium containing materials are desirable for a number of applicationswhere a stable chromium oxide forms in air to protect the surface fromoxidation, acid attack, and sulfur corrosion. In the instance of Fe, Co,and/or Ni-based alloys, chromium oxides (as well as aluminum oxides) areformed selectively to create a passivated surface. However, prior toforming this selective oxide layer, other metallic elements will oxidizeuntil the chromium oxide forms a continuous layer.

After the formation of a dense chromium oxide layer, exposure to hightemperatures (e.g., greater than 500° C.) in air causes thickening ofthe chromium oxide scale, where chromium diffuses out of the bulk metaland into the scale, and oxygen diffuses from the air into the scale.Over time, the scale growth rate slows as the scale thickens because (1)oxygen diffusion is slower and (2) chromium becomes depleted in the bulkalloy. For alloys, if the chromium concentration falls below athreshold, other oxides may begin to form which cause the spallation orfailure of the previously protective scale.

To extend the life of a chromium-containing alloy, one or more of thefollowing methods can be used. In one or more embodiments, the methodcan include depositing an oxide layer matching the composition andcrystal structure of the native oxide to produce the protective coating.In other embodiments, the method can include depositing an oxide layerwith a different crystal structure to the native oxide to produce theprotective coating. In some embodiments, the method can includedepositing an oxide layer with additional dopants that would not bepresent in the native oxide to produce the protective coating. In otherembodiments, the method can include depositing another oxide (e.g.,silicon oxide or aluminum oxide) as a capping layer or in a multi-layerstack to produce the protective coating.

In one or more embodiments of the method, a non-native oxide may beinitially deposited onto the surface of the metal surface of aerospacecomponent or other substrate that effectively thickens the oxide,thereby slowing oxygen diffusion toward the metal surface and resultingin slower absolute thicknesses growth of the oxide film. In someexamples, a benefit of this approach can be contemplated in the contextof a parabolic oxide scale growth curve. At thicker scales (e.g.,greater than 0.5 micron to about 1.5 micron), the rate of scalethickness decreases versus initial growth. By depositing an oxide filmhaving a thickness of about 100 nm, about 200 nm, or about 300 nm toabout 1 micron, about 2 micron, or about 3 micron prior to the growth ofa thick scale. The effective growth rate of the first thickness of about0.5 micron to about 1 micron of native scale can be much slower over agiven period of time. In turn, the rate of depletion of chromium fromthe substrate can be slower, and the time a surface can be exposed tothe environment can be longer.

Oxygen diffusion can further be slowed by depositing a predeterminedcrystalline structure of chromium oxide, e.g., amorphous. Oxygen candiffuse along grain boundaries faster than in bulk crystals for chromiumoxide, so minimizing grain boundaries can be beneficial for slowingoxygen diffusion. In turn, scale growth can be slower, and the time asurface can be exposed to the environment can be longer.

In other embodiments, the method can include incorporating one or moredopants into the deposited oxide while producing the protective coating.The dopant can be or include a source for aluminum, yttrium, hafnium,silicon, tantalum, zirconium, strontium, lanthanum, neodymium, holmium,barium, lutetium, dysprosium, samarium, terbium, erbium, thulium,titanium, niobium, manganese, scandium, europium, tin, cerium, or anycombination thereof. The dopant can segregate to grain boundaries andmodify grain boundary diffusion rates to slow the rate of oxide scalegrowth.

In one or more embodiments, an aerospace component includes a coatingdisposed on a surface of a substrate. The surface or substrate includesor contains nickel, nickel superalloy, aluminum, chromium, iron,titanium, hafnium, alloys thereof, or any combination thereof. Thecoating has a thickness of less than 10 μm and contains an aluminumoxide layer. In some examples, the surface of the aerospace component isan interior surface within a cavity of the aerospace component. Thecavity can have an aspect ratio of about 5 to about 1,000 and thecoating can have a uniformity of less than 30% of the thickness acrossthe interior surface.

Embodiments of the present disclosure further relate to any one or moreof the following paragraphs:

1. A method for depositing a coating on an aerospace component,comprising: sequentially exposing the aerospace component to a chromiumprecursor and a reactant to form a chromium-containing layer on asurface of the aerospace component by an atomic layer depositionprocess.

2. A method for depositing a coating on an aerospace component,comprising: forming a nanolaminate film stack on a surface of theaerospace component, wherein the nanolaminate film stack comprisesalternating layers of a chromium-containing layer and a second depositedlayer; sequentially exposing the aerospace component to a chromiumprecursor and a first reactant to form the chromium-containing layer onthe surface by atomic layer deposition, wherein the chromium-containinglayer comprises chromium oxide, chromium nitride, or a combinationthereof; and sequentially exposing the aerospace component to a metal orsilicon precursor and a second reactant to form the second depositedlayer on the surface by atomic layer deposition, wherein the seconddeposited layer comprises aluminum oxide, aluminum nitride, siliconoxide, silicon nitride, silicon carbide, yttrium oxide, yttrium nitride,yttrium silicon nitride, hafnium oxide, hafnium nitride, hafniumsilicide, hafnium silicate, titanium oxide, titanium nitride, titaniumsilicide, titanium silicate, or any combination thereof.

3. The method of paragraph 1 or 2, wherein the chromium precursorcomprises bis(cyclopentadiene) chromium, bis(pentamethylcyclopentadiene)chromium, bis(isoproplycyclopentadiene) chromium, bis(ethylbenzene)chromium, chromium hexacarbonyl, chromium acetylacetonate, chromiumhexafluoroacetylacetonate, a chromium diazadienyl, isomers thereof,complexes thereof, abducts thereof, salts thereof, or any combinationthereof.

4. The method of paragraph 3, wherein the chromium diazadienyl has achemical formula of:

wherein each R and R′ is independently selected from H, C1-C6 alkyl,aryl, acyl, alkylamido, hydrazido, silyl, aldehyde, keto, C2-C4 alkenyl,alkynyl, or substitutes thereof.

5. The method of paragraph 4, wherein each R is independently C1-C6alkyl which is selected from methyl, ethyl, propyl, butyl, or isomersthereof, and R′ is H.

6. The method of paragraph 4, wherein R is tert-butyl and R′ is H.

7. The method of paragraph 4, wherein the chromium diazadienyl ischromium(II) bis(1,4-ditertbutyldiazadienyl).

8. The method according to any one of paragraphs 1-7, wherein thereactant comprises a reducing agent and the chromium-containing layercomprises metallic chromium.

9. The method of paragraph 8, wherein the reducing agent compriseshydrogen (H₂), ammonia, hydrazine, a hydrazine, an alcohol, acyclohexadiene, a dihydropyrazine, an aluminum containing compound,abducts thereof, salts thereof, plasma derivatives thereof, or anycombination thereof.

10. The method according to any one of paragraphs 1-9, wherein thereactant comprises an oxidizing agent and the chromium-containing layercomprises chromium oxide.

11. The method of paragraph 10, wherein the oxidizing agent compriseswater, oxygen (O₂), atomic oxygen, ozone, nitrous oxide, a peroxide, analcohol, plasmas thereof, or any combination thereof.

12. The method according to any one of paragraphs 1-11, wherein thereactant comprises a nitriding agent and the chromium-containing layercomprises chromium nitride.

13. The method of paragraph 12, wherein the nitriding agent comprisesammonia, atomic nitrogen, a hydrazine, plasmas thereof, or anycombination thereof.

14. The method according to any one of paragraphs 1-13, wherein thereactant comprises a carbon precursor or a silicon precursor and thechromium-containing layer comprises chromium carbide or chromiumsilicide.

15. The method of paragraph 14, wherein the carbon precursor comprisesan alkane, an alkene, an alkyne, substitutes thereof, plasmas thereof,or any combination thereof, and the silicon precursor comprises silane,disilane, substituted silanes, plasmas thereof, or any combinationthereof.

16. The method according to any one of paragraphs 1-15, furthercomprising forming a nanolaminate film stack on the surface of theaerospace component, wherein the nanolaminate film stack comprisesalternating layers of the chromium-containing layer and a seconddeposited layer.

17. The method of paragraph 16, wherein the second deposited layercomprises aluminum oxide, aluminum nitride, silicon oxide, siliconnitride, silicon carbide, yttrium oxide, yttrium nitride, yttriumsilicon nitride, hafnium oxide, hafnium nitride, hafnium silicide,hafnium silicate, titanium oxide, titanium nitride, titanium silicide,titanium silicate, or any combination thereof.

18. The method of paragraph 16, wherein the chromium-containing layercomprises chromium oxide, chromium nitride, or a combination thereof,and wherein the second deposited layer comprises aluminum oxide, siliconnitride, hafnium oxide, hafnium silicate, or any combination thereof.

19. The method of paragraph 16, wherein the alternating layers in thenanolaminate film stack comprises from 1 pair to about 50 pairs of thechromium-containing layer and the second deposited layers.

20. The method of paragraph 16, wherein the second deposited layer isdeposited by atomic layer deposition.

21. The method of paragraph 16, further comprising annealing theaerospace component and converting the nanolaminate film stack into acoalesced film.

22. The method according to any one of paragraphs 1-21, wherein theaerospace component is a turbine blade, a turbine vane, a supportmember, a frame, a rib, a fin, a pin fin, a combustor fuel nozzle, acombustor shield, an internal cooling channel, or any combinationthereof.

23. The method according to any one of paragraphs 1-22, wherein thesurface of the aerospace component is an interior surface of theaerospace component.

24. The method according to any one of paragraphs 1-23, wherein thesurface of the aerospace component is an exterior surface of theaerospace component.

25. The method according to any one of paragraphs 1-24, wherein thesurface of the aerospace component comprises nickel, nickel superalloy,aluminum, chromium, iron, titanium, hafnium, alloys thereof, or anycombination thereof.

26. An aerospace component, comprising: a surface comprising nickel,nickel superalloy, aluminum, chromium, iron, titanium, hafnium, alloysthereof, or any combination thereof; and a coating having a thickness ofless than 10 μm and disposed on the surface, wherein the coatingcomprises a chromium-containing layer, and wherein thechromium-containing layer comprises metallic chromium, chromium oxide,chromium nitride, chromium carbide, chromium silicide, or anycombination thereof.

27. An aerospace component, comprising: a surface comprising nickel,nickel superalloy, aluminum, chromium, iron, titanium, hafnium, alloysthereof, or any combination thereof; and a coating having a thickness ofless than 10 μm and disposed on the surface, wherein the coatingcomprises aluminum oxide.

28. An aerospace component, comprising: a surface comprising nickel,nickel superalloy, aluminum, chromium, iron, titanium, hafnium, alloysthereof, or any combination thereof; and a coating on the surface,wherein the coating is deposited by atomic layer deposition andcomprises a chromium-containing layer, and wherein thechromium-containing layer comprises metallic chromium, chromium oxide,chromium nitride, chromium carbide, chromium silicide, or anycombination thereof.

29. The aerospace component according to any one of paragraphs 26-28,wherein the surface of the aerospace component is an interior surfacewithin a cavity of the aerospace component, wherein the cavity has anaspect ratio of about 5 to about 1,000, and wherein the coating has auniformity of less than 30% of the thickness across the interiorsurface.

30. The aerospace component according to any one of paragraphs 26-29,wherein the aerospace component is a turbine blade, a turbine vane, asupport member, a frame, a rib, a fin, a pin fin, a combustor fuelnozzle, a combustor shield, an internal cooling channel, or anycombination thereof.

31. The aerospace component according to any one of paragraphs 26-30,wherein the surface has a cavity with an aspect ratio of greater than 5to 1,000.

32. A method for depositing a coating on an aerospace component,comprising: exposing an aerospace component to a first precursor and afirst reactant to form a first deposited layer on a surface of theaerospace component by a chemical vapor deposition (CVD) process or afirst atomic layer deposition (ALD) process; and exposing the aerospacecomponent to a second precursor and a second reactant to form a seconddeposited layer on the first deposited layer by a second ALD process,wherein the first deposited layer and the second deposited layer havedifferent compositions from each other.

33. A method for depositing a coating on an aerospace component,comprising: forming a nanolaminate film stack on a surface of theaerospace component, wherein the nanolaminate film stack comprisesalternating layers of a first deposited layer and a second depositedlayer; sequentially exposing the aerospace component to a firstprecursor and a first reactant to form the first deposited layer on thesurface by atomic layer deposition, wherein the first deposited layercomprises chromium oxide, chromium nitride, aluminum oxide, aluminumnitride, or any combination thereof; and sequentially exposing theaerospace component to a second precursor and a second reactant to formthe second deposited layer on the first deposited layer by atomic layerdeposition, wherein the second deposited layer comprises aluminum oxide,aluminum nitride, silicon oxide, silicon nitride, silicon carbide,yttrium oxide, yttrium nitride, yttrium silicon nitride, hafnium oxide,hafnium nitride, hafnium silicide, hafnium silicate, titanium oxide,titanium nitride, titanium silicide, titanium silicate, or anycombination thereof, and wherein the first deposited layer and thesecond deposited layer have different compositions from each other.

34. The method of paragraph 32 or 33, wherein the first deposited layeris formed by the first ALD process and the method further comprisessequentially exposing the aerospace component to the first precursor andthe first reactant to form the first deposited layer.

35. The method of paragraph 34, wherein each cycle of the first ALDprocess comprises exposing the aerospace component to the firstprecursor, conducting a pump-purge, exposing the aerospace component tothe first reactant, and conducting the pump-purge, and each cycle isrepeated from 2 times to about 500 times to form the first depositedlayer prior to forming the second deposited layer.

36. The method according to any one of paragraphs 32-35, wherein thefirst deposited layer is formed by the CVD process and the methodfurther comprises simultaneously exposing the aerospace component to thefirst precursor and the first reactant to form the first depositedlayer.

37. The method according to any one of paragraphs 32-36, wherein thefirst deposited layer comprises chromium oxide, chromium nitride,aluminum oxide, or aluminum nitride, wherein the second deposited layercomprises aluminum oxide, aluminum nitride, silicon oxide, siliconnitride, silicon carbide, yttrium oxide, yttrium nitride, yttriumsilicon nitride, hafnium oxide, hafnium nitride, hafnium silicide,hafnium silicate, titanium oxide, titanium nitride, titanium silicide,titanium silicate, or any combination thereof, and wherein if the firstdeposited layer comprises aluminum oxide or aluminum nitride, then thesecond deposited layer does not comprises aluminum oxide or aluminumnitride.

38. The method according to any one of paragraphs 32-37, wherein thefirst precursor comprises a chromium precursor or an aluminum precursor,and the first reactant comprises an oxidizing agent, a nitriding agent,or a combination thereof.

39. The method according to any one of paragraphs 32-38, wherein thesecond precursor comprises an aluminum precursor or a hafnium precursor,and the second reactant comprises an oxidizing agent, a nitriding agent,or a combination thereof.

40. The method according to any one of paragraphs 32-39, wherein thefirst precursor comprises bis(cyclopentadiene) chromium,bis(pentamethylcyclopentadiene) chromium, bis(isoproplycyclopentadiene)chromium, bis(ethylbenzene) chromium, chromium hexacarbonyl, chromiumacetylacetonate, chromium hexafluoroacetylacetonate, a chromiumdiazadienyl, isomers thereof, complexes thereof, abducts thereof, saltsthereof, or any combination thereof.

41. The method of paragraph 40, wherein the chromium diazadienyl has achemical formula of:

wherein each R and R′ is independently selected from H, C1-C6 alkyl,aryl, acyl, alkylamido, hydrazido, silyl, aldehyde, keto, C2-C4 alkenyl,alkynyl, or substitutes thereof.

42. The method of paragraph 40, wherein each R is independently C1-C6alkyl which is selected from methyl, ethyl, propyl, butyl, or isomersthereof, and R′ is H.

43. The method of paragraph 40, wherein R is tert-butyl and R′ is H.

44. The method of paragraph 40, wherein the chromium diazadienyl ischromium(II) bis(1,4-ditertbutyldiazadienyl).

45. The method according to any one of paragraphs 32-44, wherein thefirst precursor or the second precursor comprises an aluminum precursor,and wherein the aluminum precursor comprises a tris(alkyl) aluminum, atris(alkoxy) aluminum, aluminum diketonates, complexes thereof, abductsthereof, salts thereof, or any combination thereof.

46. The method of paragraph 45, wherein the aluminum precursor comprisestrimethylaluminum, triethylaluminum, tripropylaluminum,tributylaluminum, trimethoxyaluminum, triethoxyaluminum,tripropoxyaluminum, tributoxyaluminum, aluminum acetylacetonate,aluminum hexafluoroacetylacetonate, trisdipivaloylmethanatoaluminum,isomers thereof, complexes thereof, abducts thereof, salts thereof, orany combination thereof.

47. The method according to any one of paragraphs 32-46, wherein thefirst precursor or the second precursor comprises a hafnium precursor,and wherein the hafnium precursor comprises bis(methylcyclopentadiene)dimethylhafnium, bis(methylcyclopentadiene) methylmethoxyhafnium,bis(cyclopentadiene) dimethylhafnium, tetra(tert-butoxy) hafnium,hafniumum isopropoxide, tetrakis(dimethylamino) hafnium (TDMAH),tetrakis(diethylamino) hafnium (TDEAH), tetrakis(ethylmethylamino)hafnium (TEMAH), isomers thereof, complexes thereof, abducts thereof,salts thereof, or any combination thereof.

48. The method according to any one of paragraphs 32-47, wherein ananolaminate film stack comprises the first deposited layer and thesecond deposited layer, and the method further comprises depositing from2 pairs to about 500 pairs of the first deposited layer and the seconddeposited layer while increasing a thickness of the nanolaminate filmstack.

49. The method of paragraph 48, wherein each pair of the first depositedlayer and the second deposited layer has a thickness of about 0.2 nm toabout 50 nm.

50. The method of paragraph 48, further comprising annealing theaerospace component and converting the nanolaminate film stack into acoalesced film.

51. The method of paragraph 47, wherein the first deposited layercomprises aluminum oxide and the second deposited layer compriseshafnium oxide, and wherein a concentration of hafnium is about 0.01 at %to about 10 at % within the nanolaminate film stack.

52. The method of paragraph 48, wherein the nanolaminate film stack hasa thickness of about 1 nm to about 5,000 nm.

53. The method according to any one of paragraphs 32-52, wherein theaerospace component is a turbine blade, a turbine vane, a supportmember, a frame, a rib, a fin, a pin fin, a combustor fuel nozzle, acombustor shield, an internal cooling channel, or any combinationthereof.

54. The method according to any one of paragraphs 32-53, wherein thesurface of the aerospace component is an interior surface of theaerospace component, and wherein the surface of the aerospace componentcomprises nickel, nickel superalloy, aluminum, chromium, iron, titanium,hafnium, alloys thereof, or any combination thereof.

55. The method according to any one of paragraphs 32-54, wherein thesurface of the aerospace component has a cavity with an aspect ratio ofgreater than 5 to 1,000.

56. An aerospace component, comprising: a surface comprising nickel,nickel superalloy, aluminum, chromium, iron, titanium, hafnium, alloysthereof, or any combination thereof; and a coating disposed on thesurface, wherein the coating comprises a nanolaminate film stackcomprising alternating layers of a first deposited layer and a seconddeposited layer; wherein the first deposited layer comprises chromiumoxide, chromium nitride, aluminum oxide, aluminum nitride, or anycombination thereof; wherein the second deposited layer comprisesaluminum oxide, aluminum nitride, silicon oxide, silicon nitride,silicon carbide, yttrium oxide, yttrium nitride, yttrium siliconnitride, hafnium oxide, hafnium nitride, hafnium silicide, hafniumsilicate, titanium oxide, titanium nitride, titanium silicide, titaniumsilicate, or any combination thereof; wherein the first deposited layerand the second deposited layer have different compositions from eachother; and wherein the nanolaminate film stack has a thickness of about1 nm to about 5,000 nm.

57. The aerospace component of paragraph 56, wherein the aerospacecomponent is a turbine blade, a turbine vane, a support member, a frame,a rib, a fin, a pin fin, a combustor fuel nozzle, a combustor shield, aninternal cooling channel, or any combination thereof.

58. The aerospace component of paragraph 56 or 57, wherein the surfaceof the aerospace component is an interior surface within a cavity of theaerospace component.

59. The aerospace component according to any one of paragraphs 56-58,wherein the cavity has an aspect ratio of about 5 to about 1,000.

60. The aerospace component according to any one of paragraphs 56-59,wherein the coating has a uniformity of less than 30% of the thicknessacross the interior surface.

While the foregoing is directed to embodiments of the disclosure, otherand further embodiments may be devised without departing from the basicscope thereof, and the scope thereof is determined by the claims thatfollow. All documents described herein are incorporated by referenceherein, including any priority documents and/or testing procedures tothe extent they are not inconsistent with this text. As is apparent fromthe foregoing general description and the specific embodiments, whileforms of the present disclosure have been illustrated and described,various modifications can be made without departing from the spirit andscope of the present disclosure. Accordingly, it is not intended thatthe present disclosure be limited thereby. Likewise, the term“comprising” is considered synonymous with the term “including” forpurposes of United States law. Likewise whenever a composition, anelement or a group of elements is preceded with the transitional phrase“comprising”, it is understood that we also contemplate the samecomposition or group of elements with transitional phrases “consistingessentially of,” “consisting of”, “selected from the group of consistingof,” or “is” preceding the recitation of the composition, element, orelements and vice versa.

Certain embodiments and features have been described using a set ofnumerical upper limits and a set of numerical lower limits. It should beappreciated that ranges including the combination of any two values,e.g., the combination of any lower value with any upper value, thecombination of any two lower values, and/or the combination of any twoupper values are contemplated unless otherwise indicated. Certain lowerlimits, upper limits and ranges appear in one or more claims below.

What is claimed is:
 1. An aerospace component, comprising: a surfacecomprising nickel, nickel superalloy, aluminum, chromium, iron,titanium, hafnium, alloys thereof, or any combination thereof; and acoating disposed on the surface, wherein the coating comprises ananolaminate film stack comprising two or more pairs of a firstdeposited layer and a second deposited layer; wherein the firstdeposited layer comprises chromium oxide, chromium nitride, aluminumoxide, aluminum nitride, or any combination thereof; wherein the seconddeposited layer comprises aluminum oxide, aluminum nitride, siliconoxide, silicon nitride, silicon carbide, yttrium oxide, yttrium nitride,yttrium silicon nitride, hafnium oxide, hafnium nitride, hafniumsilicide, hafnium silicate, titanium oxide, titanium nitride, titaniumsilicide, titanium silicate, or any combination thereof; wherein thefirst deposited layer and the second deposited layer have differentcompositions from each other; and wherein the nanolaminate film stackhas a thickness of about 1 nm to about 5,000 nm.
 2. The aerospacecomponent of claim 1, wherein the coating is a coalesced film disposedon the surface, the coalesced film is formed by annealing thenanolaminate film stack.
 3. The aerospace component of claim 1, whereinthe nanolaminate film stack comprises from 3 pairs to about 1,000 pairsof the first deposited layer and the second deposited layer.
 4. Theaerospace component of claim 1, wherein the coating has a uniformity ofless than 50% of the thickness of the coating.
 5. The aerospacecomponent of claim 4, wherein the coating has a uniformity of about 1%to about 30%.
 6. The aerospace component of claim 1, wherein the surfaceof the aerospace component is an interior surface within a cavity of theaerospace component.
 7. The aerospace component of claim 6, wherein thecavity has an aspect ratio of greater than
 2. 8. The aerospace componentof claim 7, wherein the cavity has an aspect ratio of greater than 5 to1,000.
 9. The aerospace component of claim 1, wherein the aerospacecomponent is a turbine blade, a turbine vane, a support member, a frame,a rib, a fin, a pin fin, a combustor fuel nozzle, a combustor shield, aninternal cooling channel, or any combination thereof.
 10. The aerospacecomponent of claim 9, wherein the aerospace component is a turbineblade.
 11. The aerospace component of claim 1, wherein the surface ofthe aerospace component comprises nickel or a nickel superalloy.
 12. Theaerospace component of claim 1, wherein each of the first depositedlayer and the second deposited layer independently has a thickness ofabout 0.1 nm to about 150 nm.
 13. The aerospace component of claim 1,wherein the first deposited layer comprises aluminum oxide and thesecond deposited layer comprises hafnium oxide, and wherein aconcentration of hafnium is about 0.01 at % to about 10 at % within thenanolaminate film stack.
 14. The aerospace component of claim 1, whereinthe nanolaminate film stack has a thickness of about 1 nm to about 5,000nm.
 15. An aerospace component, comprising: a surface comprising nickelor nickel superalloy; and a coating disposed on the surface, wherein thecoating comprises a coalesced film formed by annealing a nanolaminatefilm stack which comprises two or more alternating layers of a firstdeposited layer and a second deposited layer; wherein the firstdeposited layer comprises chromium oxide, chromium nitride, aluminumoxide, aluminum nitride, or any combination thereof; wherein the seconddeposited layer comprises aluminum oxide, aluminum nitride, siliconoxide, silicon nitride, silicon carbide, yttrium oxide, yttrium nitride,yttrium silicon nitride, hafnium oxide, hafnium nitride, hafniumsilicide, hafnium silicate, titanium oxide, titanium nitride, titaniumsilicide, titanium silicate, or any combination thereof; wherein thefirst deposited layer and the second deposited layer have differentcompositions from each other; and wherein the nanolaminate film stackhas a thickness of about 1 nm to about 5,000 nm.
 16. The aerospacecomponent of claim 15, wherein the nanolaminate film stack comprisesfrom 3 pairs to about 1,000 pairs of the first deposited layer and thesecond deposited layer.
 17. The aerospace component of claim 15, whereinthe coating has a uniformity of less than 50% of the thickness of thecoating.
 18. The aerospace component of claim 15, wherein the surface ofthe aerospace component is an interior surface within a cavity of theaerospace component, and wherein the cavity has an aspect ratio ofgreater than
 2. 19. The aerospace component of claim 18, wherein thecavity has an aspect ratio of greater than 5 to 1,000.
 20. A turbineblade, comprising: a surface comprising nickel or nickel superalloy; anda coating disposed on the surface, wherein the coating comprises acoalesced film formed by annealing a nanolaminate film stack whichcomprises two or more alternating layers of a first deposited layer anda second deposited layer; wherein the first deposited layer compriseschromium oxide, chromium nitride, aluminum oxide, aluminum nitride, orany combination thereof; wherein the second deposited layer comprisesaluminum oxide, aluminum nitride, silicon oxide, silicon nitride,silicon carbide, yttrium oxide, yttrium nitride, yttrium siliconnitride, hafnium oxide, hafnium nitride, hafnium silicide, hafniumsilicate, titanium oxide, titanium nitride, titanium silicide, titaniumsilicate, or any combination thereof; wherein the first deposited layerand the second deposited layer have different compositions from eachother; and wherein the nanolaminate film stack has a thickness of about1 nm to about 5,000 nm.